Computer networks are often used in today's society to transfer data. A computer network is formed by network devices, referred to as nodes, that are physically and virtually interconnected. The network devices may communicate with one another using different protocols, such as Asynchronous Transfer Mode (“ATM”) or Internet Protocol (“IP”).
Multiprotocol Label Switching (“MPLS”) technology improves network traffic flow and management for communications using these and other protocols. MPLS involves setting up a specific path for a sequence of data packets. Each node in the path receives a data packet and then forwards the packet to the next node in the path until the data packet reaches its intended destination. By labeling each packet, MPLS saves time needed for a node to look up the address to the next node in the path when forwarding the packet.
MPLS may be used to support Transport LAN Services (“TLS”), which may involve transmitting a data packet from one source point of a network to more than one destination point. This is referred to as a point-to-multipoint (“P2MP”) transmission or “multicasting.” To support multicasting, a source node using MPLS often establishes multiple point-to-point tunnels (referred to as “unicast” tunnels) with intermediate nodes to form paths to the destination nodes. Each unicast tunnel is operable to carry one data packet at a time from one node to another node.
The number of unicast tunnels needed between a source node and an intermediate node may depend on the number of destination nodes that are downstream from the source node. For example, if a source node is associated with three destination nodes through an intermediate node, then three unicast tunnels may be required between the root node and the intermediate node so that the intermediate node may receive three of the same data packet. Then the intermediate node forwards the three packets to the three respective destination nodes. Having three unicast tunnels between the root node and the intermediate node requires three different bandwidths to be reserved using three pairs of resource reservation (“RSVP”) connections.